Use pkgconfig() build dependencies

[skip changelog]

Signed-off-by: Nils Philippsen <nils@tiptoe.de>

sord.spec

@@ -10,10 +10,10 @@ URL:        https://drobilla.net/software/%{name}.html
 Source0:    https://download.drobilla.net/%{name}-%{version}.tar.xz
 
 BuildRequires: doxygen
-BuildRequires: serd-devel >= 0.30.10
 BuildRequires: gcc
 BuildRequires: meson
-BuildRequires: pcre-devel
+BuildRequires: pkgconfig(libpcre)
+BuildRequires: pkgconfig(serd-0) >= 0.30.10
 
 %description
 %{name} is a lightweight C library for storing Resource Description